There is a great value to self-examination within the day to day walk with and after Christ, but it ought to be more than a solely self-examination. It is why the Psalmist prayed, "Search me O God, and know my heart; test me and know my thoughts. See if there is any wicked way in me, and lead me in the way everlasting." (Ps. 139:23-24) When we do the necessary work of self-examination we must invite God to search along with us and reveal the things He will. We do this because when left to our own, we have two primary tendencies, both of which are destructive to the honest heart after God.
Our first tendency is to praise ourselves too highly. If we do not ask God to search our hearts and reveal, we will make excuses for every wicked or troublesome thing in our heart and mind. We will make light of dark things, which ought to be dealt with.
Our other tendency is to blame ourselves too heavily. If we do not ask God to search and reveal, we will tirelessly break ourselves down. For some of us God is entirely more gracious toward our sin than we would ever dream of being for ourselves.This is why we need God to search and reveal our true heart's condition.
God is fully aware of our tendency toward one of these extremes (I find myself in the latter most often). Because He is aware of our tendency, and because He knows too much SELF-examination does more harm than good, He presents in the Psalms how we ought to search and reveal the sin in our lives. We go about this with humility and grace, only God can accomplish that balance with perfection. Only God will draw us in humility and grace for self in order to balance between the extremes of praise and blame.